Interferon-mediated block in cell cycle and altered integrin expression in a differentiated salivary gland cell line (HSG) cultured on Matrigel.

Sjögren's syndrome (SS), an idiopathic, autoimmune exocrinopathy, is partly characterized by diminished salivary flow, acinar cell atrophy, and increased expression of several cytokines. Several in vivo characteristics of the sialoadenitis are also evident in a human salivary gland ductal epithelial cell line (HSG) treated with cytokines. HSG cells differentiate to the acinar phenotype when cultured on Matrigel (Becton Dickinson, Bedford, MA), a basement membrane extract. To elucidate mechanisms of salivary gland pathology, the effects of interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) on cell cycle progression and integrin expression were evaluated in HSG acinarlike cells. Flow cytometry experiments showed that cytokine treatment for 2 days arrested cells in G(1) phase of the cell cycle, and this preceded significant morphologic changes and decreased viability. Whereas only modest cytokine-mediated increases in protein expression for the alpha 3 and beta 1 integrin subunits were seen by immunoprecipitation, a form of alpha 3 integrin displaying enhanced electrophoretic mobility was evident after 6 days of cytokine treatment. To our knowledge, this is the first report demonstrating an IFN-mediated alteration in the electrophoretic mobility of integrin subunits. From this study, it was evident that the combination of IFN-gamma and TNF-alpha resulted in a block in G(1) phase for acinar cells before accumulation of the alpha 3 integrin variant or significant degenerative cellular changes. Information from the present and previous studies suggests that cytokines may alter the pattern of integrin expression and block cell cycle progression in salivary gland cells grown in three-dimensional acinarlike clusters. These experiments may provide a new cell culture model to study the effects of cytokines in normal and diseased salivary glands, including SS.

Estrogen receptor level and other factors in early recurrence of breast cancer.

At the time of treatment in 1977 for primary breast cancer of all stages, the tumors of 270 women were examined for estrogen-receptor (ER) content by isoelectric focusing on polyacrylamide gel. The procedures for the initial and follow-up examinations were standardized. Postoperative adjuvant radiotherapy or chemotherapy was given to pre- and postmenopausal women aged up to 70 years with nodal involvement. Adjuvant tamoxifen treatment (20 mg twice daily for 2 years) was given to one-half of the postmenopausal patients aged 70 years or less, selected at random, and irrespective of any other adjuvant therapy. These forms of treatment appeared not to introduce bias into the results of the study. There was no correlation between the ER content and tumor spread. Symptom-free survival during the follow-up period was best for the patients with tumors with a high ER content, poorer for the patients with tumors of intermediate ER content and least favorable for patients with tumors having low ER content. (Ranges for high, intermediate and low levels: 2.18-9.08, 0.13-2.17 and 0-0.12 fmoles/microgram DNA). The differences between the survival curves were significant. For the 120 operable patients with nodal involvement there were also significant differences in recurrence-free survival. The premenopausal patients in this group likewise showed a significant difference in survival with respect to ER content. For the operable patients with nodal involvement and poorly differentiated tumors there was also a difference in the survival rate depending on the ER content. In this study the ER content of breast cancer was shown to be a quantitative rather than a qualitative entity. The study confirms the independent prognostic importance of the ER content and points to its potential value as a stratification criterion in adjuvant therapy trials.